import scipy.signal

class DSPProcessor:
    def apply_eq(self, signal: np.ndarray, freqs: List[float], gains: List[float]) -> np.ndarray:
        """应用均衡器"""
        for f, g in zip(freqs, gains):
            signal = scipy.signal.butter(3, f, 'band', output='sos', fs=44100)
        return signal